The United States is on the verge of a national crisis that could mean the end of clean, cheap water.

Hundreds of cities and towns are at risk of sudden and severe shortages, either because available water is not safe to drink or because there simply isn't enough of it.

The situation has grown so dire the U.S. Office of the Director of National Intelligence now ranks water scarcity as a major threat to national security alongside terrorism.

The problem is being felt most acutely in the West, where drought conditions and increased water use have helped turn lush agricultural areas to dust.

But dangers also lurk underground, in antiquated water systems that are increasingly likely to break down or spread contaminants like lead.

The crisis gripping Flint, Mich., where the water supply has been rendered undrinkable, is just a preview of what's to come in towns and cities nationwide, some warn.

"We are billions of dollars behind where we could and should be," said Rep. Jared Huffman (D-Calif.), who spent 12 years on a municipal water board before running for state office. "People in the clean-water world would tell you they've been shouting about this for a long time."

"For much of the U.S., most people don't perceive any shortage," he added. "But we're going to talk a lot about shortages now."

'A huge problem nationwide'

Perhaps the single biggest threat to the water supply, experts say, is the nation's aging infrastructure.

Across the country, water is flowing through pipes that are long past their expiration date.

Some of the oldest pipes still in use, built from cast iron in the late 1880s, were expected to last about 120 years. Newer pipes, built during the post-World War II boom, were designed to last about 75 years.

"It's a huge problem nationwide," said Erik Olson, director of the health and environment program at the Natural Resources Defense Council (NRDC). "A lot of [the water infrastructure is] now 100 years old or more. We haven't been taking care of it."

"Flint is just one example, but there are literally thousands of systems across the country that are having serious compliance problems, serious lead problems," he added.

In 2001, a report from the National Water Works Foundation predicted an "inexorable rise in infrastructure replacement needs" in water systems if they were not replaced.

In the next 20 years, the Environmental Protection Agency (EPA) estimates the total cost of revitalizing water pipes and treatment plants would run about $384 billion.

The American Water Works Association's estimates are even higher.

The nonprofit group says the cost of just maintaining current systems and fitting them to the needs of a growing population would require $1 trillion over 25 years. Without that funding, customers will see drastic changes in their water services, including increased risks of lead contamination.

While the price tag is daunting, advocates and lawmakers argue the costs of inaction are far greater.

"The first reaction we always get when we talk about going big on infrastructure is 'who's going to pay for it.' We all pay for it if we don't invest," said Rep. Dan Kildee (D-Mich.), who represents Flint.

"The Flint case makes it clear that there are real human and tangible consequences of our failure to deal with water infrastructure," he added.

Lead risks

Lead water pipes were prevalent in the United States until the late 1980s, when the EPA first started setting policies to prevent lead from getting into public water systems.

Huffman, a two-term congressman serving on the House Committee on Natural Resources, said the Flint water crisis should spur officials around the country to test their systems, even if they're afraid of what they'll find.

"We have to build on the increased awareness that we have right now and really go around the country and go to communities where there is a reasonable possibility of this kind of contamination and do the testing and ask the hard questions," Huffman said.

Not every city has turned a blind eye to the problem.

Leaders in Madison, Wis., began replacing lead pipes almost immediately after the EPA tightened lead standards in 1991. The project cost $15.5 million and spanned 11 years, ultimately resulting in the removal of 8,000 lead water pipes, according to NPR.

Similarly, the city of Wichita, Kan., is about to complete a decade-long project to replace about 1,500 lead service pipes with copper or plastic. Public works teams replaced between 100 and 200 per year, with each pipe costing about $1,200.

Other cities are eyeing similar strategies. Lansing, Mich. — about 60 miles away from Flint — unveiled a plan this spring to replace its lead pipes.

One burst at a time

Local governments are also grappling with the problem of pipes bursting and leaking.

Water main breaks are becoming more common, according to the American Society of Civil Engineers, which estimated that there are about 240,000 each year.

In a few spots in the U.S., including South Dakota and Washington, some people are reportedly relying on wooden pipes.

Some of the water main breaks have caused massive damage to surrounding areas.

The city of Troy, N.Y., declared a state of emergency in January 2016 after a water main break flooded several streets and distrusting life in several neighboring towns. The year before, the town of Brockton, Mass., was forced to close schools and limit hospital services as it raced to fix a pipe that had burst.

In 2009, the mayor of Warren, Mich., called a state of emergency after the town suffered 107 breaks in one month and needed to call in out-of-town workers.

When the breaks occur, little is done beyond patching the broken lines.

Olson, of the NRDC, said that if water lines continue to be replaced at the current rate, it will take 200 years to replace all of them.

In the meantime, more lead problems are likely. The school district in Newark, N.J., recently replaced water fountains with bottled water after finding unacceptably high levels of lead in the tap water.

Jeff Griffiths, a Tufts University public health professor and former chairman of the EPA's drinking water committee, predicted more communities would be finding lead in school water.

"The bubblers, the fixtures that are there, might well have lead in them," he said.

Worsening droughts

Some parts of the country have a bigger problem than corroding pipes: there is simply a lack of water.

While the drought conditions in California have received the lion's share of media attention, the problem is widespread. In 2014, water managers in 40 out of 50 states said they expected a water shortage that year, according to a federal watchdog report.

The scarcity is only expected to get worse.

A study last year by NASA asserted that climate change could increase the risk of decades-long "megadroughts" that could make entire regions of the country nearly uninhabitable. The droughts, NASA warned, could last for as long as 35 years.

And even if greenhouse gas emissions were entirely eliminated by the middle of this century, the chance of a megadrought would remain over 60 percent, NASA said.

The risks are particularly high in the Southwest and Central Plains, where booming cities like Phoenix and Las Vegas are surrounded by desert.

The problem persists despite a significant decline in America's water use since 1980, thanks to more efficient water systems in homes and offices and on farms.

Officials in charge of public water supplies say new water-saving technologies are within reach if the government makes funding a priority.

Earlier this year, the White House called for $25 million for desalination research to make the process of turning salt water into drinking water cheaper and more efficient.

But many are skeptical that seawater is the answer. In addition to its immense costs and energy requirements, draining the oceans could have disastrous consequences for marine life.

One alternative could be reusing wastewater, which is happening now at a plant in Orange County, Calif., that opened in 2008. The facility takes wastewater from the sanitation department and purifies it into drinking water.

"I do see climate change and decreasing amounts of water meaning that water is going to need to be reused," said Griffiths, the Tufts professor.

Battle in Congress

Federal lawmakers have sought to address the water issue but have made little headway.

One of the biggest bills on water scarcity to come before Congress recently dealt with drought relief for California.

A bill that passed the House last year, spearheaded by Majority Leader Kevin McCarthy (R-Calif.), would have authorized two water storage projects that Republicans say are long overdue. It called for a new system of dams, reservoirs and aqueducts to help move water from California's wetter areas to its dryer ones.

That bill went nowhere in the Senate, where California's Democratic Sens. Barbara Boxer and Dianne Feinstein pushed for a dramatically different set of remedies.

The Democrats' plan calls for new desalination, efficiency and recycling projects, which they argue would be more reliable in the long term, even if it wouldn't be satisfactory to California's agricultural interests.

"Obviously there is a real conflict of visions, and we understand the, shall we call it, philosophy, that more water is just growth-inducing and they don't want to see growth," Rep. Ed Royce (R-Calif.), who helped move the House bill, said in a recent interview.

"It's not as though we don't have a blueprint or strategy to deal with the problem. It's the blocking and tackling that's done at the federal agencies or Gov. [Jerry] Brown's," Royce said.

Work on the drought legislation remains at an impasse.

The end of cheap water?

If water companies don't see funding from the government to fix water infrastructure, they could force their customers to pick up the tab.

The American Water Works Association estimates that in the hardest-hit areas, families' water bills could triple.

"In order to achieve progress toward clean water goals and simultaneously sustain the existing water infrastructure, user rates will have to continue to increase," the U.S. Conference of Mayors said in a 2013 report.

Part of the challenge going forward, experts say, is that water is almost entirely managed, delivered and paid for at the local level.

The federal government has some oversight power to ensure cities and towns are meeting standards of the Safe Drinking Water Act. But the programs are modest, and the funding has been slashed dramatically.

For cities like Flint, which suffered from the recession more than the average town, the water problems were compounded.

Mick Bullock, government affairs director for the National Conference of State Legislatures, said local water managers are in a "really rough place" as they try to keep their systems from falling apart.

"They don't really have the money to do what Congress requires them to do; they really rely on state and locals to do their jobs for them," he said.

The most successful tyranny is not the one that uses force to assure uniformity but the one that removes the awareness of other possibilities, that makes it seem inconceivable that other ways are viable, that removes the sense that there is an outside.